"As a parent, I know how fixated kids can be with their electronic devices, but we have to get our kids moving," says Mr Sinclair.

Heart Foundation CEO Mary Barry says nearly a quarter of the 9,000 students in years 8 to 11 who were surveyed are either overweight or obese.

"Overweight and obesity among young people is a significant public health issue in Australia, with overweight adolescents being at increased risk of becoming overweight adults and experiencing chronic diseases such as heart disease," Ms Barry said.

Nearly 80 per cent of Australian teenagers are clocking up more than two hours of screen time on school days, compared with 71 per cent in 2009.

And 89 per cent are exceeding the recommended two hours of screen time per day on weekends, up from 83 per cent in 2009.